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Advanced Security14 min read • January 30, 2025

How to use two locks for maximum security

One lock says "secured." Two locks scream "find an easier target." Master the two-lock technique that forces thieves to carry double the tools, spend double the time, and usually just walk away. Here's exactly how to make your bike the one they skip.

Daniel Kim

Daniel Kim

Urban Cycling Security Expert

Why two locks work

Bike thieves are specialists. They carry specific tools for specific locks and work on tight timelines. Two different locks destroy their business model:

  • Tool specialization: Angle grinder guy can't defeat hydraulic jacks
  • Time pressure: Doubling work time quadruples risk
  • Visual deterrent: Screams "high security" from 50 feet
  • Economics: Why fight two locks when single-locked bikes exist?

Picture a thief approaching your bike. They see one lock—standard procedure. They see two different locks—instant calculation: double the tools, double the time, double the risk. Nine times out of ten, they keep walking.

The golden combinations

Best: U-lock + Heavy chain

Why this works

  • • U-lock: Compact, defeats leverage attacks
  • • Chain: Flexible, resists angle grinders longer
  • • Different cutting techniques required
  • • Both can be Sold Secure Gold/Diamond

Implementation

U-lock: Rear wheel + frame to rack (tight fit)
Chain: Front wheel + frame + rack (flexible routing)

Pro tip: "I use HipLok 1.5 chain and Knog Strongman U-lock downtown. Never had an attempt in 5 years of NYC commuting." - Real cyclist

Good: U-lock + Folding lock

Advantages

  • • Lighter total weight
  • • Easy to carry both
  • • Good for medium-risk areas
  • • Folding lock adds flexibility

Limitations

  • • Folding locks weaker than chains
  • • Similar attack profiles
  • • Not for overnight parking
  • • Check insurance requirements

Budget: Small U-lock + Cable extension

Reality check: Cable locks are easily cut, but better than leaving wheels unsecured. Use only as wheel deterrent with strong primary lock.

  • • U-lock: Frame + rear wheel (primary security)
  • • Cable: Loop through front wheel (visual deterrent)
  • • Upgrade to chain when budget allows
  • • Never rely on cable as primary lock

Strategic lock placement

The 60-second lockup

1.

Assess the anchor (5 seconds)

  • • Verify rack is secure (shake test)
  • • Check for pre-cut damage
  • • Ensure proper height/thickness
2.

Position strategically (10 seconds)

  • • Rear wheel against rack
  • • Minimize ground clearance
  • • High-value components facing in
3.

Primary lock application (20 seconds)

  • • U-lock through rear triangle
  • • Capture rim, not just tire
  • • Minimize internal space
  • • Keyhole facing down
4.

Secondary lock routing (20 seconds)

  • • Chain through front wheel + frame
  • • Different attachment point if possible
  • • Cross pattern for visual impact
  • • Tighten all slack
5.

Final check (5 seconds)

  • • Test both locks engaged
  • • No rattling or movement
  • • Remove accessories

Weight vs. security calculation

The eternal dilemma: security weighs heavy. Here's how to optimize:

Lock weight reality

Lightweight combo (4-6 lbs)

Medium Security

Mini U-lock + folding lock. Good for low-risk quick stops.

Standard combo (7-10 lbs)

High Security

Standard U-lock + 10mm chain. Daily commuter sweet spot.

Maximum combo (12-15 lbs)

Maximum Security

Fahgettaboudit U-lock + 14mm chain. For overnight/high-value bikes.

Pro tip: Leave heavy lock at regular destinations. Carry lighter lock for flexibility.

Special situations

Overnight parking

Never rely on single locks overnight. Thieves have time and darkness:

  • Use heaviest chain + U-lock combo available
  • Consider third lock for high-value bikes
  • Indoor storage always preferred
  • GPS tracker as backup

Quick stops (under 5 minutes)

Even quick stops need proper security:

  • Minimum: One Gold-rated lock properly applied
  • Better: Light U-lock + cafe lock combo
  • Never: Just a cafe lock or cable

E-bike considerations

E-bike security requirements

  • • E-bikes 3x more likely to be stolen
  • • Battery adds vulnerability (secure separately)
  • • Insurance often requires Diamond/Gold locks
  • • Two-lock method strongly recommended
  • • Consider integrated alarm systems

Common two-lock mistakes

  1. Same lock types: Two U-locks = same vulnerabilities
  2. Cheap secondary: Bronze lock undermines Gold primary
  3. Poor placement: Both locks on same anchor point
  4. Loose application: Space allows tool insertion
  5. Predictable routine: Same locks, same spot daily

Real-world success stories

Cyclist testimonials

"Five years in San Francisco with two locks. Witnessed three theft attempts on nearby single-locked bikes. Mine never touched."

- Daily commuter

"Found cut marks on my chain lock. U-lock untouched. Two locks saved my $3,000 e-bike—thief gave up halfway."

- E-bike owner

"Insurance required two Gold locks for coverage. Haven't had a claim in 8 years. Best investment ever made."

- Urban cyclist

The investment perspective

Quality two-lock setup costs $150-300. Compare to:

  • Average stolen bike value: $500-1,500
  • Time lost dealing with theft: 20+ hours
  • Insurance deductibles: $250-500
  • Emotional cost: Priceless

Two good locks pay for themselves by preventing one theft.

Making it practical

Daily implementation tips

Carrying strategies

  • • Frame mount for U-lock
  • • Pannier for chain lock
  • • Leave one at work/gym
  • • Cargo bike advantage

Time savers

  • • Practice at home first
  • • Consistent lock order
  • • Quick-release U-lock mounts
  • • Keychain organization

The bottom line

Two locks transform your bike from "easy target" to "not worth it." Yes, they're heavier. Yes, they take longer. But ask anyone who's had a bike stolen—they'd gladly carry four locks to prevent that experience.

Start with one quality lock. Add a second when you can. Your future self, still riding the same bike, will thank you.

Upgrade to two-lock security

Don't wait for theft to teach you this lesson. Invest in proper two-lock security today.